1

Master Thesis

Institute of Applied Geosciences Graz University of Technology

Institute of Earth Sciences

University of Graz

The Influence of extensive Slope Tectonics on the h ydro geological System Roach Spring

(Carinthia/Austria)

Author

Raphael Staunig

Advisors

VAss. Mag. Dr. Gerfried Winkler Univ.-Prof. Mag. Dr. Walter Kurz

2

STATUTORY DECLARATION

I declare that I have authored this thesis independently, that I have not used other than the

declared sources / resources and that I have explicitly marked all material which has been

quoted either literally or by content from the used sources.

…………………………… ……………………………………………….. date (signature)

3

Acknowledgements

4

Index Contents 4 Abbrevations and definitions 6 Abstract 7 Kurzfassung 7 1 Introduction 1.1 Idea 8 1.2 Geographic Overview 9 2 Basics 2.1 Geologic Overview 11 2.1.1 Klagenfurt Basin 13 2.1.2 Regional Structures 14 2.1.3 Detailed geological overview of Turiawald 15 2.1.4 Geomorphology and mass movements 18 2.2 Hydrogeologic Overview 20 2.3. Theory of mass movements and deformation 22 2.3.1 Formation and classification 22 2.3.2 The system “hard on soft” 24 2.4 Structural geology and tectonics 25 2.5 Theory of discharge analysis 26 2.5.1 Hydrograph 26 2.5.2 Quotient of discharge 26 2.5.3 Coefficient of discharge 27 2.5.4 Variations of parameters 29 3 Methods 3.1 Field mapping 30 3.2 Structural analysis 31 3.3 Analysis of lineaments and topography 31 3.4 Hydrogeologic monitoring 32 4 Results 4.1 Structural geology 33 4.1.1 Outcrop St.Ruperti 35 4.1.2 Outcrop Oberdoerfl 35 4.1.3 Turiawald rock faces 33 4.2 Geomorphology 38 4.2.1 Regional lineaments 38 4.2.2 Turiawald plateau 40 4.2.3 Turiawald western slope 43 4.3 Hydrogeology 4.3.1 Hydrogeologic mapping 47 4.3.2 Hydrogeologic monitoring 48 4.2.4 Resources of water 54 4.2.5 Aquiclude of western Turiawald 57 5. Discussion Interpretation 5.1 Structural geology and geomorphology 58 5.1.1 Turiawald Plateau 58 5.1.2 Mass Movement of western slope 59 5.2 Hydrogeology 61 5.2.1 Analysis and interpretation of hydrograph and parameter graphs 61 5.2.2 Aquiclude morphology 63

5

6. Conclusion 6.1. Failure mechanism and kinematics 64 6.2 Hydrogeology 66 7.Literature 67

6

Abbrevations and definitions

centimetre = cm

electric conductivity = ec

digital elevation model = dem

discharge = litres per second = (l/s)

figure = fig.

joint openings = open discontinuities with an aperture of more than one metre

litres = (l)

metre = m

meters above sea level = m.a.s.l.

micro Siemens per centimetre = µs/cm

millimetre = mm

million = mill.

square kilometre = km²

table = tab.

temperature ° Celsius = T°C

7

Abstract

The conglomerate plateau Turiawald is the catchment area for several springs featuring

strongly varying discharge rates. Discharge and parameters of the two strongest discharging

springs, Roach and Pleier, have been monitored for a year and compared, to obtain specific

discharge characteristics. Geological field mapping and data analysis has been done to

describe geological influences on the springs.

Above Roach spring a large scale mass movement is situated, which influences both

aquiclude and aquifer, the first is displaced and deformed by the movement, the latter

features fast infiltration and discharge through joint conduits of in suit rock mass and voids

provided by mass movement debris.

Roach is in hydrogeologic ways categorized as spring with characteristics of a karst spring,

Pleier as spring connected to a jointed aquifer with more narrow fissures. The deformation of

Turiawald Plateau and its foreland is classified as system “hard on soft”, the resulting mass

movement of its western slope is categorized as complex mass movement.

Large scale lineaments affecting both bedrock and top layers of the investigated area are

related to the Periadriatic line as Riedel shears.

Kurzfassung Das Konglomeratplateau Turiawald ist das Einzugsgebiet für mehrere Quellen mit stark

unterschiedlichen Schüttungen. Schüttung und Geländeparameter der zwei am stärksten

schüttenden Quellen, Pleier und Roach, wurden über ein Jahr regelmäßig gemessen und

verglichen, um Kenntnis über die spezifischen Schüttungsverhalten zu erhalten.

Geländekartierungen und deren Auswertung wurden für die Beschreibung des geologischen

Einflusses auf die Quellen durchgeführt.

Die Roach Quelle liegt am Fuß einer Massenbewegung, welche sowohl den

Grundwasserstauer als auch den –Leiter beeinflusst, ersterer wird verlagert und deformiert,

letzterer zeigt schnelle Infiltration und große Schüttungsmengen durch Kluftgasen und den

Porenraum des Massenbewegungskörpers.

Die Roach Quelle zeigt Eigenschaften einer Karstquelle, Pleier is hauptsächlich an einen

Kluftgrundwasser gebunden. Die Deformation des Turiawald Plateaus kann als „hart auf

weich“ System klassifiziert werden, die resultierende Massenbewegung am Westhang als

komplexe Massenbewegung. Regionale Lineamente die als Riedel Scherflächen zu

Periadriatischen Linie angesehen werden können, beeinflussen sowohl Hangend- wie auch

Liegendschichten des Arbeitsgebietes

8

1 Introduction

1.1 Idea Primary target of this thesis is to describe the influence of a large scale mass movement and

its geologic properties in interplay with the hydrogeologic system Roach spring, which is

located at the base of the mass movement. The spread and type of the mass movement and

the mode of failure are of interest, if possible for both in situ rock mass and blocks of the

mass movement. Furthermore, the position of the aquiclude on western slope of the working

area should be determined.

For comparison, a spring which is draining the same geologic catchment area, Pleier Spring,

but not situated close to a mass movement body is monitored too.

Further topics of interest are characterisation of the two investigated springs in hydrogeologic

ways, differentiation of base flow and event water and an estimation of the theoretical

available resources of water. To get a representative data base for this task, both springs are

monitored by data loggers for a year.

Probably linked to failure kinematics of the mass movement and the structure of the

stratigraphic top layers in this region are also regional geological factors, which are affecting

the basement rocks of the investigated area. The structural situation of this formations is also

to be described and interpreted.

9

1.2 Geographic Overview

The Sattnitz Mountains are located north of the Karawanken Mountains on the southern rim

of the Klagenfurt basin in Carinthia, Austria. The 30 km long, 7 km wide and up to 900 meter

high plateau-like ridge is west-east oriented. It features several rock faces up to 100 meter

high and is divided by the north-south striking Köttmannsdorfer depression into eastern

Sattnitz and western Sattnitz. The westernmost part of the latter is the Turiawald (Turia

Forrest), the focus of this study, which is a plateau situated close to the villages Roach and

Penken (fig.1). The investigated area Turiawald and its western foreland are completely

covered by woodland.

(fig.1) upper figure shows map of Sattnitz Mountains, Carinthia, blue rectangle marks the study area;

scale 1:175000, lower figure shows enhanced view of blue rectangle, map of Turiawald scale 1:23000

(BEV, 2010)

10

The Sattnitz Mountains are affected by several mass movements and slope instabilities,

ranging in scale from minor scarps and tilted blocks to mountain splitting phenomena.

Furthermore, this uplands function as catchment area for several springs which are used as

drinking water supply for the adjacent communities.

.

11

2 Basics

2.1 Geologic Overview

In the southeastern Alps the Periadriatic Line, a fault system crossing the alps from the

Thyrrenian sea to the Pannonian basin, separates the Southalpine unit from the northern

Central Austroalpine unit (fig.2) (Laubscher 1970, 1983, 1988, Bögel 1975, Schmid et al.

1989, von Gosen 1989).

(fig.2) Geologic map of the Eastern Alps, blue rectangle marks the study area (modified after Kurz

2010, unpublished map with courtesy of Kurz)

Both Central Austroalpine and Southalpine units comprise Permo-Mesozoic platform strata

as cover which rest on metamorphosed Paleozoic Variscan basement (Brandner 1972,

Bögel 1975, Niedermayr 1975, Tollmann 1977, Laubscher 1988).

Along the Periadriatic Line, the Austroalpine basement, which is part of the Gurktal Nappe

system, includes Ordovician metavolcanoclastics, micaschists, phyllites, marbles and

Permian granite, which is overlain by Permian redbeds. Central Austroalpine cover is an 3.4

km thick Upper Permian to Lower Cretaceous sequence, mainly consisting of dolomite and

limestone units of the Triassic Wetterstein and Hauptdolomit formations, which are overlain

by basinal Jura to Cretaceous limestones and marls (Schönlaub 1979, Bauer et al. 1983). As

12

uppermost part, Neogene syntectonic clastics of the Klagenfurt basin overly the Austroalpine

strata (Polinski et al.1992). The Southalpine unit is 3,2 km thick and consists of Ordivician to

Lower Carboniferous metasediments as basement, overlain by Upper Carboniferous to

Jurassic sedimentary strata, mainly marine clastics and carbonates (Schönlaub 1979, Bauer

et al. 1983) (fig.3).

The Karawanken Mountains consist of both Austroalpine and Southalpine units and straddle

the Peradriatic fault. Miocene dextral strike slip deformation along this fault zone and thrust

displacement along the northern Karawanken front initiated the subsidence of the Klagenfurt

basin (Polinski et al.1992).

(fig.3) Stratigraphic units of the Austroalpine and Southalpine facies domains juxtaposed along the

Periadriatic Line and showing the distinct mismatch of sedimentary facies. Triassic stages are

abbreviated with letters. Potential detachment horizons within the Mesozoic cover sequence are

indicated by open arrows (Polinski et al.1992).

13

2.1.1 Klagenfurt Basin

The Klagenfurt Basin is an E/W orientated intra orogenic basin of Sarmatian to Quarternary

age (fig.4) (Nemes et al.1997). During late Miocene, upwards NW directed nappe stacking

and flexure of the Austroalpine lithosphere was initiated by loading through the Karawanken

unit during its approach from the south, kinematically connected to brittle transpressive strike

slip deformation along the Periadriadic Fault (Nemes et al.1997). The final northwest directed

overthrust of the Karawanken unit over the Neogene Sediments of its foreland took place in

Pliocene times. Linked to brittle transpressive shearing along the Periadriatic fault the basin

and a positive flower structure were formed, the foreland was flexured again (fig.5, Nemes et

al.1997).

(fig.4) Location of Klagenfurt Basin (Nemes et al.1997)

The Stratigraphy of the Klagenfurt Basin comprises a more than 1000 m thick Sarmatian to

Quarterny sequence, deposited on Austroalpine basement units, which starts with the

Rosenbach Formation (early Sarmatium), containing limnic, coal bearing, fine grained

sediments (Kahler 1953). The formation is divided into a lower, coal bearing part and a

coarsening upward sequence. Lower coal bearing sections include mudstones, sandstones

and coarse conglomerates with interbedded carbonate, while the upper sequence of the

Rosenbach Formation comprises over 100m thick coarse conglomerate bearing derived from

the uprising Karawanken Mountains and rocks from the Austroalpine metamorphic basement

with some mud- and sand bearing clastics interbedded (Papp 1951, Klaus 1956; Tollmann

1985). These are again overlain by tick coarse carbonate bearing conglomerates. The

Bärental Conglomerate overlies the latter with a thickness of several 100 m (Pannonium -

14

Pontium ), northward it grades into the Penken Formation , a coal bearing up to 50m thick

siltstone layer (Pontium) (Kahler 1953). The uppermost most part of the stratigraphic

sequence is the up to 200m thick Sattnitz Conglomerate (Pliocene - Pleistocene) (Tollmann

1985).

2.1.2 Regional Structures

The Periadriatic Fault and its related structures are a first order boundary between

Austroalpine and Southapline units. Miocene top to the northwest nappe stacking north of the

Periadriatic Fault was followed by overthrusting of the Karawanken massive which formed a

positive flower structure, associated with flexure of the foreland and formation of the

Klagenfurt basin (Nemes et al.1997). Final NNW directed overthrust of the Karawanken

Mountains onto the foreland is characterized by NW–SE striking dextral tear faults and NW

to NNW directed thrust planes in the Neogene Sediments of the Klagenfurt basin (fig.6).

NNW-SSE directed contraction formed transpressional structures depicted by NNW-directed

thrusts and SSE-directed backthrusts, NW-striking dextral faults (R faults), and NE-striking

sinistral faults (R' faults) (Nemes et al.1997). To the south, both Rosenbach Formation and

the overlying Bärental Conglomerate are overthrusted by the North Karawanken unit and

folded, indicating a reverse anticline, while S-dipping thrusts and reverse faults override the

Sattnitz Conglomerate (Kahler 1953).

(fig.5) Sketch showing Karawanken overthrust onto the foreland ("positive flower structure") (Nemes et

al.1997

15

2.1.3 Detailed geological overview of Turiawald

The NW/SE striking Hochstuhl fault (fig.6) intersects the Periadriatic Fault and divides

paleozoic basement and permotriassic cover units west of Turiawald in western and eastern

parts. To the west a greenschist metamorphic phyllite basement is overlain by permotriassic

clastic conglomerates, quarzites, sandstones (Werfener Schichten) and triassic carbonates

(Anisium) (Claasen et al. 1987). Eastern of the fault diaphtorites, micaschists, marbles,

phyllites, isolated amphibolites and greenschists build up prepermian basement units, which

are overthrusted by dolomites of Anisian and Ladinian age, as well as Triassic calcitic marble

(Claasen et al. 1987). Mylonitisation occurs in both basement and cover rocks along their

shear planes, especially dolomites show fault breccias and cataclasites. Younger Triassic to

Jurassic units were propably sedimented, but have been eroded in upper Cretaceous times

(Claasen et al. 1987). Lithologies are displayed in (fig.7).

(fig.6) sketch map and cross section of Hochstuhl Fault and Periadriatic Line SW of Turiawald

(modified after Polinski et al.1992)

Two prealpine and three alpine deformations affected both paleozoic and permotriassic

rocks. While prealpine deformations are not preserved, the alpine deformations can be

16

distinguished (Claasen et al. 1987). First alpine deformation led to folding with NNW/SSE to

NNE/SSW striking b-axes which dip to the south in phyllites and marbles, where also joints

parallel to b-axes opened. Second alpine deformation created N vergent W/E striking folds

which dip to the west, additionally, in permotriassic carbonatic and clastic rocks, particularly

in dolomites, N/S striking vertical joints as well as two conjugated sets of oblique fractures

opened. During second deformation also fault breccias and cataclasites were formed in

dolomites (Claasen et al. 1987). Third alpine deformation is only poorly preserved.

Miocene brittle tectonics formed nearly vertical NNE/SSW to NNW/SSE striking faults which

affect both paleozoic and permotriassic rocks. Their striking is also parallel to joints formed

during first alpine deformation. NW/SE striking faults can be found in marbles west of

Turiawald (Hochstuhl fault, fig.6), and Triassic dolomites of Kathreinkogel show NW/SE joints

that are not related to alpine deformation. Further western a nearly vertical, south dipping,

W/E orientated normal fault exists (Claasen et al. 1987).

Two lithostratigraphic units of neogene age can be differentiated at the Turiawald Plateau

(fig. 7 and 8):

The footwall comprises the basal fine clastics of the Penken Formation, 30 to 70 meters thick

limnic sediments with coal deposits interbedded in the upper parts of the strata (Pontium).

The hanging wall is the Sattnitz Conglomerate, 150 to 200m thick and in general dipping flat

towards south with some sandstone layers in between (Pliocene-Pleistocene) (Griem et

al.1992). It contains coarse clastic gravel and is divided into two conglomerate types: Type

Tanzboden has more than 74% carbonatic gravel or less than 10% crystalline gravel, type

Turia has less than 60% carbonatic gravel or more than 18% crystalline gravel (Griem et

al.1992), lithologies are displayed in (Fig.7). The major part of its in a carbonatic matrix

enbedded components were sedimentated during the uprising of the Karawanken Mountains,

the crystalline components origin from western and northwestern regions of the Central

Austroalpine unit, the Drauzug and the Tauern Window (Griem et al.1992).

17

(fig.7) Lithological map of Turiawald Plateau and its western foreland (modified after Poltnig et al.

2007)

18

The thickness of the basal fine clastics of the Penken Formation decreases from NW to SE

(fig.8), a sedimentary, discordant contact between metamorphic basement units, i.e. marbles

and diaphtorites, and the coarse clastics of the Sattnitz Conglomerate is exposed south of

Turiawald (Griem et al.1992). Coals interbedded in basal fine clastics were explored until the

1950´s, surface and subsurface mining was done on the western and northwestern slopes

below the Turiawald Plateau.

(fig.8.) sketch of cross section of Turiawald Plateau (Griem et al.1992)

2.1.4 Geomorphology and mass movements

The Sattnitz Conglomerate is divided into four separate parts by large scale lineaments.

Turiawald is separated from Tanzboden Plateau in the south east by faulting, large scale

lineaments striking N/S and NNW/SSE divide Tanzboden from the western Koettmannsdorf

area and a NW/SE striking lineament seperates the latter from eastern Koettmannsdorf area

(Winkler et al. 2008).

The western Sattnitz Mountains are affected by several small and large scale mass

movements, downward moving conglomerate blocks appear along the entire border of the

Plateau. North of western Sattnitz Mountains is the large scale mass movement of Dobein

located, with an extend of about 4,5 square kilometres (Fellner 1993). Moraine sediments

found in this area indicate glacial overprint (Poltnig et al. 2007).

19

The Tanzboden Plateau in the south east of Turiawald shows slope tectonic phenomena, its

western slope features tower shaped conglomerate blocks moving downwards. On the

plateau itself sinkholes and depressions can be found and it is divided by a WNW/ESE

striking fault line (Fellner 1993).

Turiawald is separated from the main conglomerate plateau and bordered by steep rock

faces, its surface shows large numbers of sinkholes and depressions. Both karstification and

tectonic movements are assumed as cause for formation of the sinkholes (Fellner 1993,

Poltnig et al. 2007). The western slope of the Turiawald is characterized by a large area

mass movement. Series of downward moving blocks have formed an undulous morphology,

depicted by wall and trench structures. At the north western break off a large conglomerate

block (about 200m in diameter) is deposed from the plateau and lowered for several meters

(Fellner 1993, Winkler et al. 2008).

During pleistocene times the overall area was covered by glacial ice. Moraine material can

be found in tectonically induced depressions, especially in the southern parts of Sattnitz

Mountains (Winkler et al 2006). During Wuerm Glacial the Sattnitz Conglomerate was

overthrusted several hundrets of metres by the Drau Glacier, which was flowing from W to E.

The glacial overprint of Sattnitz Conglomerate is assumed to be a major factor in the

formation of the mass movements (Fellner 1993).

Transport of the coarse clastic sediments to the deposition area was provided by a braided

river system, running from W to E, transgressing over afore deposited clastics and coals as

well as exposed paleozoic basement (Griem et al.1992).

20

2.2 Hydrogeologic Overview

The spring Pleier at the northern flank of Turiawald can be found at about 650 m above sea

level (fig.9). The water gallery Hojoutz is located ca. one kilometre south east of Pleier at 645

metres elevation (fig.9). At the eastern slope at an altitude between 640 and 700 meters, two

springs are situated (fig.9) where the conglomerate is in contact with the basal fine clastics.

At the southern slope, above the location St.Ruperti, two other springs at 760 and 780

meters altitude can be found (fig.9) which show only little discharge compared to the other

springs. The spring Roach is situated at ca. 550m above sea level at the base of the mass

movement on the western slope (fig.9), at a remarkably lower altitude than the anticipated

position of the neogene coal bearing fine clastics in this area (Poltnig et al. 2007).

Roach Spring has the strongest discharge of all springs of Turiawald (ca.75 % of the total

discharge, Poltnig et al. 2007) and is being used as drinking water supply. Pleier and Hojoutz

Springs are also being used as drinking water resources and show relatively higher

discharge compared to southern and eastern springs of Turiawald (Poltnig et al. 2007).

The plateau is underlain by impermeable rocks and shows no surface water runoff, therefore

the whole infiltrating precipitation (excluding evaporation) is drained by spring discharge.

Spring discharge from surface runoffs and springs of adjacent areas show in comparison,

that discharge from Turiawald is evenly balanced, which also indicates that all infiltrating

precipitation is drained by the known springs at the plateaus escarpents ( Poltnig et al. 2007).

The hydrologic recharge area Turiawald (6.1 square kilometres, fig.9) shows for the years

2005 to 2006 an average discharge of 106,1 (l/s). Roach Spring has a recharge area of 3,9

km² and discharges 88,3 (l/s) in average, Pleier Spring has 0,8 km² recharge area and an

average outflow of 17,8 (l/s) (including Hojoutz water gallery discharge). Discharge volumes

of the single springs described above are given in (fig.9). The groundwater measured at the

springs is well stored and has an age of approximately five years (Poltnig et al. 2007).

The N and NW parts of the Sattnitz Conglomerate of Turiawald are underlain by neogene

fine clastics of the Penken Formation (fig.8), the S and SE parts by prepermian marbles and

diaphtorites (Griem et al.1991, Poltnig et al. 2007). The conglomerate and its debris acts as

an aquifer, the subjacent clastic and crystalline rocks as an aquiclude (Poltnig et al. 2007).

All springs seem to be more or less located at the contact between aquifer and aquiclude

(fig.9). The aquiclude run is not verified on the western slope, due to the influence of the

mass movement in this area. It is assumed that the aquiclude is displaced and deformed by

slope tectonics (Winkler et al 2008, Poltnig et al. 2007).

21

(fig.9) Turiawald Plateau, hydrogeologic catchment area and verified aquiclude run, size of blue dots marking springs is relative to discharge volumes from the years 2005 to 2006 (modified after Poltnig et al. 2007)

22

2.3. Theory of mass movements and deformation

2.3.1 Formation and classification

Valleys and topographic depressions are formed when glaciers and rivers cut themselves

into ground surface, normally these newly developed depressions have over steepened

slopes. Due to the attack of erosion, weathering and gravitational forces, over steepened

slopes start to flatten out by downward movement of material.

A mass movement is a valleyward directed transport of soil or rock mass which takes place if

destabilizing forces such as gravitation, water pore pressure or triggers like rapid increase of

stress (earth quakes or volcanoes) overcome retaining forces such as strength of slope

material and friction. If a mass movement has a variety of causes and fails gradually, a

trigger is not strictly necessary (Whyllie, Mah 2004).

The kind of deformation is depending on type and geological structure of rockmass or soil.

Within a mass movement several different mechanisms of deformation and movement can

take place at the same time, for instance jointed and fractured rock, weak materials or

contrast in water permeability or stiffness. Large area gravitational slope deformations of a

complete mountainside can occur at slopes that have been over steepened by glacial or

fluviatile erosion. If the glacier retreats, the ice, which acts as retaining and supporting factor

by its weight, is missing, and the slope starts to move until an equilibrium of forces is

archieved again (Hutchinson 1988, Madritsch, Millen 2007).

There are different classifications for mass movements and landslides, due to mechanic

behaviour and speed of movement the following types can be distinguished:

Creep and viscous flow are constant movements over time, a single plane of failure cannot

be determined, while sliding is a movement of rockmass along one ore more sliding planes.

Mudflow, earth flow and debris flow are types of movement in rockmass or soil which is

similar to the movement of liquids, rockfall is a very rapid failure of rockmass (Nemkoc et al.,

1972). An overview of the common basic slope failure models was discussed by Poisel and

Preh (fig.10). The following types of failure are considered to be of relevance for this thesis:

-Toppling means forward, valleywards directed rotation of blocks (fig.10i and 10j)

-Slumping refers to backwards, towards the rockface oriented rotation of blocks (fig.10d)

-Slope creep is a slow, continuous downward movemet of rock mass or debris (fig.10k)

-Translational or rotational descent of blocks separated from in situ rock mass upon an

incompetent layer, also known as “hard on soft”, this type is explained in detail in the

following chapter.

23

Two or more types of slope movement combined form a complex slope or mass movement,

it is not always possible to classify all types of these (Hutchinson 1988).

(fig.10) overview of basic modes of failure at slopes and their mechanic behaviour (Poisel & Preh,

2004)

24

2.3.2 The system “hard on soft”

A competent layer of rock which is overlying a base of incompetent material (figs.10f and 11)

is called a system of “hard on soft” (Poisel, Eppensteiner 1989). Hard corresponds to brittle

rock, soft means ductile material. Due to gravitation, the hard part starts to sink into the soft

part, which reacts with an escape movement in the direction of free foreland. The result is a

mass deficit, which causes the brittle layer to bow and finally break due to the induced stress.

Friction constrains the escape movement of the soft layer, which causes horizontal normal

tensile stress upon the brittle layer, this leads to the formation of joints and fractures with

both orthogonal and parallel direction to the border of the competent layer (fig.11) (Poisel,

Eppensteiner 1989).

These fractures separate slabs and blocks from the brittle layer, if these blocks start to move

downhill, three types of failure can be distinguished:

-translational movement of blocks (fig.11a)

-rotational movement of blocks (fig.11b and 11c):

-toppling (fig.11c),

-slumping (fig.11b)

-failure of ductile base (fig.11b) (Poisel, Eppensteiner 1989).

a b cincompetentlayer

competent layer

(fig.11) system “hard on soft”, a) translational descent of blocks, b) failure of soft base and slumping,

c) toppling of blocks (modified after Poisel, Eppensteiner 1989)

Brittle deformation of the competent layer followed by separation and displacement of blocks

very often is formed along preexisting tectonic discontinuities. During separation and

movement of blocks additional fractures can occur. Movement rates are in most cases very

slow, constant deformation rates, i.e. the missing of periods of faster deformation due to

rainfall or other external factors, indicates creeping as failure mode in the soft layer. The

existence of both translational and rotational movement is a result of the absence of a

25

continuous gliding plane. Possibly following or resulting mass movements, such as rock fall,

can be much faster (Glawe, Moser, 1989).

2.4. Structural geology and tectonics

Tectonic deformation forms planar discontinuities without displacement due to lateral

movement called joints, and discontinuities which are displaced by movement relatively to

each another called faults. Three main types of faults, normal faults (downward movement),

thrust faults (upward movement) and strike slip faults, can be observed from centimetre to

kilometre scale. Strike slip faults feature a fault plane which is usually near vertical and the

footwall moves laterally either left or right (Eisbacher 1996).

During strike slip deformation, simple shear displacement within rocks produces

characteristic fault structures that form at a specific angle to the main fault plane, called

Riedel shear planes (fig.12). The dominant set, known as R shears, are synthetic and usually

between 10° and 20° (or φ/2, φ is angle of internal friction) to the main fault trace. Secondary

sets, the antithetic R´ and X shears form at about 70° (or φ - 90°) to the main fault. P shears

are symmetric to R shears (φ/2) and Y shears parallel to the main fault. The P, X and Y

shears are generally formed in later stages after R and R´ shears (Brosch, Kurz 2008,

Meschede 1994).

(fig.12) schematic overview of Riedl shears planes and linked shears with their respective angles, α = λ = φ/2, β = φ - 90° (Kurz, Brosch 2008)

26

2.5 Theory of discharge analysis 2.5.1 Hydrograph The discharge of water from a spring is described by the flow volume of water within a given

time, this relation can be described by a hydrograph analysis, where the discharge volume

within a period of time corresponds to the plane below the graph (e.g. Hölting 2005).

rising limb recession limb

discharge peak

time

disc

harg

e

precipitation

Fig.13 schematic hydrograph

Precipitation, which builds up water storage in the catchment area, leads to an increase in

discharge, represented by a rising limb in the graph. Discharge peak is the highest point on

the graph, when the greatest amount of water is discharged and the recession limb

represents the withdrawal of water from the storage build up in the catchment area during

earlier phases of the hydrograph (fig.13) (Kresic 2007).

Discharge is influenced by the amount of rainfall, or snowmelt in spring, infiltration conditions

and size of catchment area, while the influence of precipitation on discharge depends on

pore volume or jointing of the aquifer and height of groundwater table (e.g. Hölting 2005,

Kresic 2007).

2.5.2 Quotient of discharge

Statistical analysis of discharge can be done by calculating the quotient of discharge NQ/HQ

(Hölting 2005), where NQ (l/s) is the lowest and HQ (l/s) is the highest discharge value over

a specific time period, the arithmetic mean MQ (l/s) can also be determined.

27

Areas affected by karst formations are usually characterized by a fast and high infiltration

rate of precipitation and low surface runoff, joints widened by dissolution in aquifers in

carbonate rock provide high ground water flow rates. Therefore aquifers connected to karst

formations do have little storage capacity, variable discharge and a low quotient of discharge.

Springs with small catchment areas show in most cases a fast reaction after precipitation

events (e.g. Hölting 2005). The fast increase of discharge which is observable at karstified or

strongly jointed aquifers is usually only an hydraulic reaction due to the rise of the hydraulic

potential within the aquifer (Kresic 2007).

2.5.3 Coefficient of discharge

Hydrographs can be used to make conclusions about the hydrogeologic conditions of the

catchment area. During periods without rainfall discharge decreases due to no infiltration of

precipitation water into the aquifer, the remaining discharge is called base flow. This part of

the hydrograph can be used to make a base runoff recession curve (e.g. Hölting 2005),

which can be expressed by an exponential equation (Maillet 1905):

Qt = Q0 · e−α·∆ (1)

Qt [l/s] = discharge after time lag ∆t (end of runoff recession)

Q0 [l/s] = discharge at t0 (start of runoff recession)

α [1/d] = discharge coefficient, specific for each spring

∆t [d] = time lag between Q0 and Qt in days (∆t = t - t0)

The discharge coefficient α is depending on transmissitivity and storage capacity of the

respective aquifer, the order of 10-2 imply fast discharge rates of well interconnected fissures

or karst channels in case of karst aquifers, while values of a magnitude of 10-3 represent

slower discharge from aquifers of small voids like narrow fissures and joints (Kresic 2006). If

the hydrograph is displayed as a logarithmic graph, and no serious disturbances like rapid

water inflow is present, the discharge coefficient corresponds to the inclination of the

recession straight line, different inclinations usually represent different discharge micro

regimes. The discharge coefficient α is calculated by the following equation (Maillet 1905):

α = (log Q0 – logQt) / (0,4343 * ∆t)

0,4343 = conversation factor to express discharge in volume per time

28

The coefficient of discharge allows the prediction of discharge after any assumed period of

time. In addition this coefficient can be used to calculate the theoretical total amount of

groundwater accumulated in an aquifer at the start of recession period, what is explained by

the following equation (Kresic 2006):

Vt = Qt /

Qt = discharge at time t

Vt = Volume of accumulated water above level of discharge

Springs draining karstic or highly permeable jointed aquifers often have two or three micro

regimes of discharge. These regimes are described by discharge volumes and their

respective alpha values, which indicate different porosities and storage capacities within the

aquifer as explained above. The corresponding volume of groundwater stored in the aquifer

at the beginning of the recession is the sum of the different volumes. The following equation

is assumed for three volumes (fig.14) (Kresic 2006):

V0 = [(Q01-Q02)/ 1))+ (Q02-Q03)/ 2)+ (Q03/ 3))] * 86400

V0 = total amount of groundwater stored at the start of recession period

Q01 to Q03 = discharge (l/s) at the beginning of recession, see fig.13

86400 = factor to convert days to seconds

Q02

Q03

Q01

3

Q*

(fig.14) schematic graph of recession with three micro regimes and respective volumes and values

(modified after Kresic 2006)

29

2.5.4 Variations of parameters

In karst groundwater systems, during recharge of groundwater, marked by a rising limb on

the hydrograph, variations of the electric conductivity of the water can take place. At first,

often after a long period without rainfall, the electric conductivity shows a short initial increase

at the beginning of the increase of discharge, which represents old, high mineralized

subcutaneous water (water stored close to the surface, interacting with soil CO2 and

carbonate rock) being flushed out by the hydraulic pulse (fig.15). Then the electric

conductivity decreases rapidly, since chemical reactions between recharge water and

carbonate rocks are very fast (hours to days), every deviation from background conductivity

levels can be interpreted as water moving rapidly though the aquifer, this also is valid for a

rise of temperature during a rise of discharge. Another explanation for this decrease in

electric conductivity of the water is a dilution effect by the mixing of freshly infiltrating water

with the longer stored and higher mineralized water (Sauter 1992).

Time lags of discharge and conductivity peak values are an important criterion for

quantitative analysis. They reflect the speed of response of the aquifer to infiltrating water

and reveal transit times of the water through the conduit system (i.e. joints and fractures).

The time difference between the maximum increase of discharge (arrival of fresh water

maximum at the water table) and the minimum peak of electric conductivity (arrival of new

water at the spring) is assumed to be the time for the transit of the water through the conduit

system of the aquifer (fig.15) (Sauter 1992). Springs draining karstified or intensely fractured

aquifers can react in hydraulic means within hours to a precipitation event (Kresic 2006).

(fig.15) flow path and change in spring water parameters due to recharge water (Sauter 1992)

30

3 Methods

3.1 Field mapping

Turiawald Plateau and its proximal foreland were mapped in 1:5000 scale, western slope of

the plateau was mapped in 1:2000. Additionally, two outcrops south of Turiawald, one at the

village St. Ruperti and another one near the locality Oberdoerfl were investigated. Mapping

and further analysis was based on topographical (ÖK 205 1:5000, BEV 2005), geologic and

hydrogeologic maps (KaGis Kaernten 2008, Poltnig et al. 2007), which were prepared by

ArcGis. Mapping mainly focused on structural data of in situ rock mass at outcrops and

selected inclined blocks on the slopes of Turiawald, as well as strike and number of

depressions and sinkholes on the plateau itself. If possible due to outcrop conditions,

bedding and jointing of blocks within the mass movement was measured too.

Outcrops were characterized by:

-size

-lithology

-bedding

-joints and fractures (Hancock 1984)

-brittle faults and slickensides (Meschede 1994) wherever possible with striation and

sense of displacement

-duplex thrusts (Boyer, Elliott 1982)

Dip direction and dip of planes and striation were measured at outcrops, strike of elongation

was mapped at sinkholes and depressions on the plateau surface, as well as strike of

elongation mass movement blocks on the western slope of Turiawald.

A geological compass system Clar with 360º degrees was used as mapping device. All

stereographic plots presented in this thesis display dip direction and dip in great circle and

pole plots, rose diagrams depict strike directions.

The altitude and spread of the aquiclude along western Turiawald is of great importance for

the springs in this area. To determine the position of the aquiclude (Langguth, Voigt 2004) in

the working area, wetlands and outcrops of coal and fine clastics were mapped on the

western and northern slopes, as well as tappings of springs.

31

3.2 Structural analysis

Computer aided analysis of structural data was carried out by usage of several software

programs:

Sphaira 2.0 (Porsche-Ully 2001) was used to plot bedding, duplexes and fault planes, they

are displayed as greatcircles with their respective poles in a lower hemisphere stereonet

(Lambert projection). Joints are plotted as poles and rose diagrams, lineaments as rose

diagrams only. Statistical methods were used to calculate the centres of gravity of the

different joint sets. Two small circles around the centre of gravity depict the spherical

aperture and the cone of confidence (Fisher 1953). The vector of gravity is located within the

cone with a probability given by the confidence limit. Calculations in this thesis were done

using a confidence limit of 99%.

Fabric7 (Wallbrecher 2006) was used to plot slickensides and movement sense of striation,

orientation of paleo normal stresses was calculated also using Fabric7, computing a

paleostress determination method (Angelier, Mecheler 1977).

TectonicsFB (Reiter, Acs 2011) carried out correction of striation data for slickensides.

Stereo32 (Roeller, Trepmann 2003) computed density distribution of poles.

3.3 Analysis of lineaments and topography

Lineaments obtained by field mapping and from the digital elevation model of the overall

topography of Turiawald and its surrounding forelands were analysed by usage of ArcGis

9.2, which was also used to prepare and display mapping results.

Display and analysis of lineaments was done based on a digital elevation model with a raster

spacing of 10 meter provided by Kagis Kärnten. Lineaments derived from this model and

used in figures 21b and 24 were partly prepared and provided by Winkler et al.2006.

The Visual Basic macro Polyline Angle (Zazula 2005) was used to derive Azimuth angles

from polylines drawn with ArcGis.

32

3.4 Hydrogeologic monitoring

To determine the hydraulic behaviour and discharge volumes of the two investigated springs

Roach and Pleier, as well as to obtain specific parameters such as electric conductivity and

temperature of water, data logging stations (data loggers type “Compact” by the company

Logotronic) have been installed and maintained for a period of one and a half year for this

project.

To obtain discharge, the following procedure was carried out for the stations Pleier and

Roach:

-recording of stage above the weir (every quarter of an hour) by pressure transducer

sensor, which measures the combined pressure exerted on it by the atmosphere and

the head of water above it

-measuring of temperature and electric conductivity (corrected for 25º C) by multi

parameter probe (every quarter of an hour)

-conversion of stage into discharge

To calculate water flow (total discharge) of Pleier Spring from stage records, analogue

discharge measurements (stopwatch and bucket) were taken periodically to establish a stage

discharge relation (potential function) and maintain a discharge rating curve. Each discharge

measurement is correlated to the water level at the time the measurement was taken. With

this information, discharge data can be interpolated and applied to the full range of water

level measurements (e.g. Hölting 2005).

Because of high discharge volumes and constructive form of Roach spring as well as the fact

that the spring was currently being used as drinking water supply, it was not possible to

perform analogue point measurements of water flow. To calculate discharge from water

stages, the equation for sharp crested weirs with rectangular control section was applied,

specific input data such as weir geometry measures was provided by Joanneum Research.

For comparison, spring logging data from Roach and Pleier Springs collected by Joanneum

Research in the years 2005 and 2006 (Poltnig et al. 2007) was analysed too. The

precipitation on Turiawald for the time from spring to fall 2009 was recorded by using an

analogue ombrograph.

33

4 Results 4.1 Structural geology 4.1.1 Outcrop St.Ruperti

South of Turiawald at the location St.Ruperti (fig.23), an outcrop is located, where strongly

fractured and faulted, gray coloured marbles are exposed. The bedding dips about 70º to the

south (fig.17a), four main joint sets (fig.17b and 17c) can be distinguished, one

approximately N/S striking steeper set (dip about 70º to 80º), one set with NW/SE strike (dip

80º) and two NE/SW striking sets (dip between 40º and 70º). Mostly no or only in [mm] scale

opened apertures separate joint planes.

Several forward propagating duplex thrusts (fig.17f and fig.16) intersect joints and show

mainly NE/SW striking flats and ramps, the transition bend from flat to ramp is often

characterized by cataclastic rock. Faults (fig.17d) intersect both duplex thrusts and joints,

mostly filled with cataclastic material. At two spots the marble has been worked up to a bright

gray fault breccia, weathered and covered with a yellow to brownish coating.

Slickensides (fig.17g) are nearly striking to N/S and ENE/WSW, striation mainly shows

thrusting in NW to NNW direction and sinistral W/O oriented strike slip faults. Reconstruction

of paleo stress elipsoid shows as principal normal stresses σ1: 211/36, σ2: 111/16 and σ3:

002/57 (fig.17g).

J 345/41

F 335/21

J 086/88

ramp

flat

J 345/41

F 335/21

J 086/88

ramp

flat

(fig.16): outcrop St.Ruperti, red: fault (F), pink: duplex thrusts with respective ramps and flats, blue:

joints (J),

34

a b c

d e f

g

20%

95%

40%60%80%

σ1

σ2

σ3

(fig.17): Lambert projection with structural data outcrop at St.Ruperti: a) bedding (great circles

and poles); b) joints (poles with centers of gravity); c) joints (rose diagram); d) faults (great circles

and poles); e) slickensides (great circles); f) duplex thrusts (great circles and poles, black: flat; red:

ramp); g) paleo stress anysis and principal normal stress

35

4.1.2 Outcrop Oberdoerfl

Another outcrop south of the plateau is situated about one kilometer east of St.Ruperti near

the village Oberdoerfl, again a gray, fractured calcitic marble is exposed, although less

tectonically stressed but heavily weathered. Structural data is similar to St.Ruperti, beddings

dips 50º to the south (fig.18a), three joint sets (fig.18b and 18c) are present, two nearly

corresponding to the St.Ruperti outcrop striking approximately NW/SE and SW/NE with an

almost vertical dipping, and one other more flat dipping set striking NW/SE (dip 39 º).

N

a b cc

8

(fig.18): Lambert projection with structural data, outcrop Oberdoerfl: a) bedding (great circles

and poles); b) joints (poles with centers of gravity); c) joints (rose diagram)

4.1.3 Turiawald rock faces

The Sattnitz Conglomerate of Turiawald is exposed at the plateaus up to 100 meter high,

almost vertical rock faces, especially at the northern, western and eastern flanks. It is mainly

horizontally layered (fig.19a) and shows almost no weathering or dissolution effects. At least

three approximately vertical joint sets (fig.19b and 19c) can be found all around the plateau,

predominant strike directions are N/S to NW/SE and W/E.

Open joints appear frequently at the edge of the north western and western flank, on the foot

of the rock faces the joint aperture is mainly in [cm] scale, at the crest, especially in the north

west, many joints are widened up to meter broad joint openings (fig.23), the strike of these is

mainly N/S. The strike of joints sets is in most cases approximately perpendicular or parallel

to the rock faces of Turiawald (fig.23, 19c and 21b).

At several sites along the northern western face blocks can be found, which are almost

removed from the plateau, but still have contact to the in situ rock mass, as well as blocks

36

which are already completely removed (fig.28). The inclination of their joint planes parallel to

the faces suggests slumping and toppling as future modes of failure (fig.19d), once the block

is finally removed from the rock face.

a b c

d

(fig.19): Lambert projection with structural data, rock faces of Turiawald plateau: a) bedding (great

circles and poles); b) joints (poles with centers of gravity); c) joints (rose diagram) d) vertical joints

(pink) and average face (blue) (great circles and poles)

(tab.1): Summary of structural data (centers of gravity of the bedding (SF/SS) and the joint sets (JS))

of the three compared outcrops, numbers of joint sets do not represent ranking of formation time of

joint sets

joint

set

SF/SS JS1 JS2 JS3 JS4 JS5 JS6

domain

St.Ruperti 192/70 247/80 283/70

089/83

322/68 330/39

Oberdoerfl 182/50 256/92

072/88

319/80 035/39

Turiawald 166/13 220/80

054/87

270/84

098/80

160/81

007/81

37

The joint set JS1, which occurs at all three of the investigated outcrops St.Ruperti,

Oberdoerfl and the rock faces of Turiawald plateau shows similar orientations (tab.1 and

figs.17, 18, 19), the difference between dip directions at the respective outcrops is between

10º and 25º, the respective dip angles show differences of approximately 10º (tab.1). Joint

set JS2 appears at St.Ruperti and Turiawald outcrops, differences in dip directions and

angles are around 10º (tab.1 and figs.17,19). At the sites St.Ruperti and Oberdoerfl JS3

appears showing approximately equal dip directions and dip angles with a difference of about

15º (tab.1 and figs.17,18), joint sets JS4, JS5 and JS6 only occur at their particular outcrops

(tab.1 and figs.17,18,19). The correlations between these joint sets indicate, that their

formation is caused by the same driving forces.

38

4.2 Geomorphology

4.2.1 Regional lineaments

Analysis of the digital elevation model of Klagenfurt Basin around western Sattnitz Mountains

and their foreland revealed the existence of several lineaments which feature iterative strike

directions, such as terrain edges, lake coastlines, valleys and rivers. Four predominant strike

directions can be identified: N/S, W/E, NE/SW and NW/SE (fig.20).

(fig.20): DEM of western Sattnitz Mountains and Turiawald with its foreland in scale 1:60000, main

regional lineaments of this area and corresponding lineaments of Turiawald, as well as bedding and

joint sets of the investigated outcrops with strike directions correlating to lineaments

39

The lineaments shown in (fig.20) have been selected because of their recognisability on the

DEM (resolution 10 metres) and a minimum elongation of 0,5 kilometres.

These lineaments (fig.22) correlate roughly with the strike of the respective joint sets which

can be found at the outcrops St.Ruperti, Oberdoerfl and Turiawald Rockfaces (fig.20 and

21a), as well as the main strike directions of lineaments on Turiawald plateau (fig.20 and

21b, see also fig.24).

a b

(fig.21): Lambert projection with structural data a) stike directions of joints from the investigated

outcrops, b) overall lineaments of Turiawald

PAL

R

P

R` X

(fig.22): Lambert projection with structural data, N/S, W/E, NE/SW and NW/SE lineaments shown in

(fig.20), ideal Riedel shears (R), ideal P shears (P), ideal R´ shears (R`) and ideal X shears (X),

Periadriatic Line (PAL)

Assuming, that the large scale lineaments mentioned above (fig.20), have been formed due

to deformation along the Periadriatic Line, it is possible to correlate them in kinematic ways.

The lineaments which are striking NW/SE are at an angle of about 12º to the Periadriatic Line

and can therefore be seen as Rieldel shears (fig.22). Lineaments striking in NE/SW direction

are at an angle of 14º to 19º to the Periadriatic Line and can be understood as the linked P

shears of the fault line (fig.22). N/S striking lineaments (75º to 90º) are close to the ideal

angle of R´ and X shears (fig.22), while W/E striking lineaments can be seen as Y shears

parallel to the PAL or as glacial phenomena (fig.22).

40

4.2.2 Turiawald plateau

Mapping on Turiawald plateau itself was mainly focused on sinkholes, cracks and wetlands,

due to glacial overprint during the last great ice age, outcrops for obtaining structural data

(bedding, joint sets) can only be found in very small numbers.

Sinkholes (fig.23), cracks and crate like depressions occur frequently on the western, north

western and eastern part of Turiawald plateau (fig.25). In bigger numbers they can be found

within its boundary area, but also in a distance up to 1 kilometre from the plateau margins,

mostly in the north western part (fig.26). The strike direction of these small scale lineaments

is in most cases parallel or roughly orthogonal to the escarpments, and also correlates with

strike of large scale lineaments and joint sets.

NW/SE

(fig.23): Adjacent sinkholes, line shows strike direction

The sinkholes do have in most cases a diameter of about two meters, usually groups of such

holes can be found next to each another, often arranged in a row like beads (fig.23 and

fig.26). The strike directions of these rows as well as the elongation of single holes are

mainly oriented in W/E and NE/SW to NW/SE directions (fig.23 and fig.24a). These

orientations are approximately parallel to the strike of joint sets as well as to the strike of

large scale lineaments (terrain edges, elongated depressions etc.) and plateau margins

(fig.19c, fig.24, and fig.26). The south western and eastern areas show smaller numbers of

such small scale depressions (fig.25). In the central area of the plateau, almost no small

scale sinkholes can be found, but the digital elevation model shows two roughly elliptic

shaped large scale depressions almost in the centre of Turiawald and two lowered areas in

41

the south western and north eastern parts of Turiawald (dashed envelopes in fig.25).

Turiawald shows generally an undulatory morphology.

a b

c

(fig.24): a) strike of sinkholes; b) overall lineaments (plateau edges and lineaments derived from

DEM); c) DEM of Turiawald plateau with lineaments (modified after Winkler et al.2008)

Analysis of digital height model shows a down stepping of the topography elevation of

Turiawald plateau from south east to north west:

The south easternmost flank of the plateau has a height above sea level of about 880

metres, the central part is roughly 800 metres high. In the northwest, the plateau has only an

average height of 730 metres (fig.25). The boundaries of the elevated and the sagged slabs

(dashed lines in fig.25 and fig.26) have approximately the same orientation as the strike

directions of joint sets, sinkholes and lineaments of Turiawald rock faces, mainly in NE/SW

direction (fig.24 and fig.26).

At the north western sagged slab, the most fractures, joints and sinkholes appear, the

orientation of their strike is usually roughly parallel or perpendicular to the tear off edges of

the plateau in this area (fig.26). Here also a significant number of joint openings appears,

mostly striking N/S (fig.26). Lineaments are considered to be of extensive character, due to

aperture of joint openings and sinkholes.

42

(fig.25): DEM of Turiawald average height distribution in m.a.s.l., colours illustrate elevation:

orange/yellow to bright green = 880 to 830 m, bright green to green = 830 to 750 m, green to turquoise

= 750 to 700 m, lowermost north western part (730m) is also shown in a smaller scale in fig.26

(fig.26): DEM of north western flank of Turiawald; sinkholes and their respective strike direction,

bedding, joints and joint openings.

43

4.2.3 Turiawald western slope

The western slope of the investigated plateau shows an undulatory topography of wall and

trench structures. It is characterized by a mass movement, which consist of blocks that have

been separated from the plateau and are moving downwards the slope, supported by a

matrix of conglomerate debris. The total mass movement area derived from DEM is

approximately 2.9 square kilometres.

Block sizes range from lengths of several meters up to 170 meters long bodies of

conglomerate, they appear in an elongated, rampart like form. From north to south, the

number of blocks decreases, while the overall length of blocks increases (fig.27 and fig.30).

The strike of the elongation of blocks is roughly parallel to the contour lines of the surface

topography and the plateaus tearoff edges (fig.30). The northern part of the mass movement

shows not only smaller but also blocks with a relatively small height. In comparison, in the

southern mass movement area several tower like shaped blocks can be found standing

upright. The maximum number of blocks of the investigated area can be found above Roach

Spring, these are also relatively small in size (fig.30).

0

40

80

120

160

200

leng

ht o

f blo

cks

[m]

north, 263 blocks south, 216 blocks (fig.27): Number of blocks at northern and southern areas of Turiawalds western slope in relation to

average (red block) and overall length (black line)

The western slope shows a convex topography. Elevation difference between head and toe

of the mass movement body is about 180 meters, the distance between head and toe is

about 1,2 kilometers long, the slope has an average inclination of 10º.

44

During field investigations it was observed, that the transition to the margin of the mass

movement on western slope is indicated by termination of block and mass movement bodies

occurrence and a more evenly topography (fig.30). On the northern and southern foreland of

Turiawald plateau the number of blocks strongly decreases in eastern direction, and the

topography is less undulous. Only at the easternmost slope a few blocks of similar

appearance like on western slope counterpart can be found (fig.25). These blocks already

belong to mass movement of Dobein (Fellner 1993). The mass movement borderline of

western slope derived from DEM following convex topography markers expands the mass

movement area significantly (fig.30).

2 meters

in situ block

(fig.28): Block removed from in situ rock mass at western slope of Turiawald plateau

Debris from the plateau can be found as filling material between the blocks all over the mass

movement area. At two locations debris from recent rock falls can be found directly at the

foot of the rock faces (fig.30). Coal beds and fine clastics outcrops can be found in contact

with conglomerate blocks at three sites (fig.30), both coal and conglomerate show the same

structural orientation.

Along the western slope, several tilted blocks are situated within a few meters of the in situ

rock faces (fig.28). Their tilt angles as well as varying dip angles of the nearly vertical faces,

and inclination of blocks still in contact with the face (fig.19d), indicate both rock slumping

and rock toppling as mechanism of failure.

45

To verify the assumed slumping and toppling failure of blocks, the structural data obtained

from field mapping was analysed by usage of stereographic projections. Blocks on the

northern area of the western slope which are close to the rock walls show mainly a forward

rotation what indicates toppling failure (fig.29a). Translational movements and slumping of

blocks (fig.29a) occur in lesser numbers. Blocks which are at a minimum distance of 500

meters from the escarpment show mostly slumping and some translational movement, but

almost no toppling (fig.29a).

The southern area of Turiawalds western slope shows less activity in sense of block

movement and rotation. Dip angles of blocks close to the rock face as well as of blocks more

far away show about the same relatively small values (fig.29b). Almost the same types of

movements of blocks as in the northern area do also appear here. The little variation of

bedding data values indicates much less intense movement and rotation (fig.29b)

N N

a b

(fig.29): Lambert projection with structural data, a) northern part of western slope, b) southern part,

great circle = face, green envelope is limit of in situ bedding (minimum density distribution of pole

points), black poles = bedding of blocks within 10 m of face, red poles = blocks in about 500 meters

distance of face

Several underground and open pit coal mines are known to be in this area. An adit to an

abandoned coal mine (“Augustistollen)” is located close to the escarpments (fig.27), the

gallery is striking W/E into the mass movement. In the time from spring to fall 2008 this

gallery was affected by three cave-in events, further investigation was refrained due to

anticipated danger of continuing roof falls. The observed material inside the gallery was

unconsolidated conglomerate debris ranging in size from [cm] gravels to [m] blocks. On

some spots on the roof preciptation of thin layered speleothem can be found.

46

(fig.30): Turiawald western slope mapping results, the western border of the block field on this map is

also the border of the mass movement body

47

4.3 Hydrogeology

4.3.1 Hydrogeologic mapping

To find top limit of the aquiclude in the mass movement area on the western flank of

Turiawald, the occurrence of the basal fine clastics of Penken Formation in this area was a

major target of the mapping campaign for this project. Since coal deposits are interbedded

within the clastics, they were also mapped. Wetlands, suspicious vegetation, tappings of

springs and other signs of groundwater daylighting were also of interest.

Several outcrops of coal and fine clastics, as well as two tappings of springs and three

wetland areas (fig.30) can be found on the northern part of the western slope, mainly

occuring between 610 and 660 meter above sea level, here also the entrance to an

abandoned coal mine (fig.27) is located. The southern part of the western slope did not show

any of these features.

On the Turiawald plateau itself only some minor wetlands have been found, no surface flow

of water was present.

A NE/SW striking lineament is forming a small valley which is cut into western slope, here

also Roach spring is located, which has the strongest discharge rate among the springs of

Turiawald, almost at the deepest point of the mass movement (fig.30).

48

4.3.2 Hydrogeologic monitoring

Water stage recordings by data loggers have bee conversed to discharge by weir equation

for Roach Spring, for Peier spring the following discharge rating curve (fig.31) has been

derived from stage / discharge relation:

y = 2,71621411292347000000x1,21174681745462000000

R2 = 0,72036303378218400000

0

5

10

15

20

25

30

0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 water stage (cm)

disc

harg

e (l/

s)

(fig.31): Pleier Spring discharge rating curve and its respective exponential equation

Due to weir geomtrey (two spillovers of different size) and a relatively small head above the

crest, the conditions to maintain an ideal rating curve were not perfect.

Pleier water inflow consists of three spring tappings and the overfall from the Hojoutz water

gallery, which flow into a collecting basin.

The springs Pleier and Roach show strongly different maximum and average discharge

rates, minimum values are approximately the same. Both springs show similar electric

conductivity and temperature (tab.2)

(tab.2): mean values of discharge (Q) from summer 2008 to summer 2009, electric conductivity (EC)

and temperature (T) from the springs Pleier and Roach

Q min

(l/s)

Q max

(l/s)

Q ø

(l/s)

EC min

(µS/cm)

EC max

(µS/cm)

EC ø

(µS/cm)

T min

(ºC)

T max

(ºC)

T ø

(ºC)

Pleier 9,37 20,83 13,03 306,95 316,04 312,18 7,50 8,17 7,9

Roach 9,17 402,85 99,31 296,39 321,16 310,1 7,81 8,04 7,9

49

Roach spring has a lower quotient of discharge NQ/HQ, but an higher average discharge

rate MQ. Minimum NQ, maximum HQ and mean MQ values for both measuring points are

presented in the following table (tab.3):

(tab.3): MQ, NQ, HQ and discharge quotient NQ/HQ of Pleier and Roach springs from 2005 to 2006

and 2008 to 2009, calculated from day mean values. Data from measurement campaigns 2005 and

2006 have been provided by Joanneum Research

Pleier Roach

NQ (l/s) 11,16 6,9 19,68 21,33

HQ (l/s) 43,95 21,37 529,1 403,32

MQ (l/s) 19,48 12,48 91,04 103,61

NQ/HQ (l/s) 0,25 0,32 0,04 0,05

june05-

july06

june08-

july09

june05-

july06

june08-

july09

The NQ value of Roach is 21,33 litres, what would be the minimum volume available for

discharge in the year 2008/2009, while Pleier has a minimum volume of 6,9 litres. The

differences of HQ values of 2005/2006 to the year 2008/2009 is a result of the intense

snowfalls of winter 2005/2006 and snowmelt in spring 2006.

Derived from their hydrographs, discharge coefficients of the Pleier and Roach springs have

been calculated for the time from spring to fall 2009. The hydrograph of the measuring point

Pleier shows three different coefficients of discharge (fig.32), α1 (0,011-0,014), α2 (0,002-

0,006) and α3 (0,003-0,004, see also tab.4), which appear frequently within the hydrograph

(fig.34). Roach spring shows two iterative discharge coefficients (fig.33 and fig.35), α1

(0,078-0,081) and α2 (0,020-0,035, see also tab.5).

The transition from α1 to α2 of Pleier Spring takes place at about 16 (l/s) and from α2 to α3 at

roughly 13 (l/s) (fig.34 and tab.4), transition from α1 to α2 of Roach Spring is at a discharge

rate of approximately 160 (l/s) (fig.35 and tab.5).

(tab.4): average discharge coefficients of the spring Pleier, with their respective initial (Q0 [l/s]) and

final (Qt [l/s]) discharge volumes of each base runoff recession curve (fig.32)

Pleier t0 Q0 [l/s] t Qt [l/s] ∆t [d] α [1/d]

α1 07.04.2009 20,62 27.04.2009 15,63 20 0,0125

α2 28.04.2009 15,73 19.06.2009 11,68 52 0,004

α3 27.06.2009 12,93 03.09.2009 11,15 36 0,0035

50

(tab.5): average discharge coefficients of the spring Roach, with their respective initial (Q0 [l/s]) and

final (Qt [l/s]) discharge volumes of each base runoff recession curve (fig.33)

Roach t0 Q0 [l/s] t Qt [l/s] ∆t [d] α [1/d]

α1 11.03.2009 317,4 18.03.2009 166,38 8 0,0795

α2 20.03.2009 163,64 29.03.2009 133,89 10 0,0275

Discharge coefficients α2 and α3 from the hydrograph of Pleier Spring represent a low

discharge over a long period of time, they do not differ very much in magnitude. Generally

speaking, low volume discharge is a predominant feature of Pleier spring compared to

Roach. Only α1 recession straight line shows a steeper inclination within the hydrograph,

which stands for a relatively bigger discharge (fig.32 and tab.4).

The high value coefficient α1 of Roach Spring depicts fast discharge of big volumes within a

relatively short time, low value α2 shows a slower flow out of discharge with smaller volumes

per time (fig.33 and tab.5).

3/28/09 4/27/09 5/27/09 6/26/09 7/26/09 8/25/09

10

disc

harg

e (l/

s) lo

g10

308

312

316

320

el. c

ondu

ctiv

ity µ

S/c

m c

orr.

25°

α1

α2

α3

(fig.32): extracted semilog graph from Pleier Spring hydrograph and electric conductivity graph for the

recession period from tab. showing discharge coefficients α1, α2 and α3

51

3/8/09 3/18/09 3/28/09

10

100

1000

disc

harg

e (l/

s) lo

g10

300

310

320

el. c

ondu

ctiv

ity µ

S/c

m c

orr.

25°

α1

α2

(fig.33): extracted semilog graph from Roach Spring hydrograph and electric conductivity graph for the

recession period from tab. showing discharge coefficients α1, α2

Figures 34 and 35 show the hydrographs of Pleier and Roach springs for the time from April

2008 to October 2009, as well as the respective curves for electric conductivity and

temperature, graphs are based on day mean values.

Precipitation is displayed as bar plot in (fig. 34) and (fig. 35), due to data shifts of the

ombrograph a maximum accuracy of one day can be given for the rainfall recordings.

Maximum discharge rates of both springs are reached during December and in the time from

March to April, the first because of snowmelt during a mild winter period, the latter because

of snowmelt in spring, minimum discharge flows out during summer (fig.34 and fig. 35).

Although both springs do have very different magnitudes of discharge, they show similar

electric conductivity and temperature values (fig.34 and fig.35 and tab.2), since both drain

the same hydrogeologic area Turiawald, and are affected by similar lithologies and geologic

structures (fig.7, fig.8 and fig.9).

52

6/1/08 7/31/08 9/29/08 11/28/08 1/27/09 3/28/09 5/27/09 7/26/09 9/24/09

8

12

16

20

24

28di

sch

arge

l/s

308

312

316

320

ele

ctric

cond

uctiv

ityµS

/cm

(cor

r.25)

7.2

7.6

8

8.4

8.8

tem

per

atur

e°C

80

60

40

20

0

prec

ipita

tion

(mm

)

α3 α3

α1α1 α1

α2α2

(fig.34): hydrograph of the spring Pleier (blue), with its respective electric conductivity (black) and

temperature (red) graphs, precipitation from April to September 2008 is displayed by the bar plot, α

values and their respective straight lines

α1

α2

6/1/08 7/31/08 9/29/08 11/28/08 1/27/09 3/28/09 5/27/09 7/26/09 9/24/09

0

100

200

300

400

disc

harg

el/s

300

310

320

ele

ctric

cond

uctiv

ityµS

/cm

(cor

r.25

)

7.8

7.85

7.9

7.95

8

8.05

tem

pera

ture

°C

80

60

40

20

0

pre

cipi

tatio

n(m

m)

α1

α1

α2α2

(fig.35): hydrograph of the spring Roach (blue), with its respective electric conductivity (black) and

temperature (red) graphs, precipitation from April to September 2008 is displayed by the bar plot, α

values and their respective straight lines

53

Electric conductivity of both springs is reversely proportional to the discharge, higher flow

rates are followed by decrease of conductivity. If discharge increases after a longer period of

recession, the conductivity of Roach Spring often rises up before strongly decreasing (fig.35),

while Pleier shows almost no reaction of this kind (fig. 34). Four days after a severe increase

of discharge the hydrograph of Roach spring shows maximum decrease of electric

conductivity, Pleier spring reacts much faster, the time lag between maximum rise of

discharge and maximum decrease of electric conductivity here is only fifteen hours (fig.36).

3/28

/09

3/29

/09

3/30

/09

3/31

/09

4/1/

09

4/2/

09

4/3/

09

4/4/

09

16

18

20

22

disc

harg

e(l/

s)lo

g10

308

312

316

el.c

ondu

ctiv

ityµS

/cm

corr

.25°

time lag 15 hours

a b3/28

/09

3/29

/09

3/30

/09

3/31

/09

4/1/

09

4/2/

09

4/3/

09

4/4/

09

4/5/

09

4/6/

09

4/7/

09

4/8/

09

4/9/

09

4/10

/09

100

200

300

400

500

disc

harg

e(l/

s)lo

g10

300

310

320

el.c

ondu

ctiv

ityµS

/cm

corr

.25°

time lag 4 days

(fig.36): time lags between strongest increase of discharge and maximum decrease of electric

conductivity, a) Roach Spring, b) Pleier Spring

Changes in temperature due to discharge variation are little at Roach and almost not

observable at Pleier. Single strong precipitation events cause an increase of the flow rate at

Roach Spring within a single day, Pleier shows a lower hydraulic reaction to a recharge input

pulse, with a time lag of one to three days between an increase of discharge and the

precipitation event (fig.34 and fig.35).

54

4.2.4 Resources of water

As shown in chapter 4.3.2, data gained from spring logging was calculated to establish

recession straight lines and α values. For further analysis and interpretation of the

hydrographs falling limb, the theoretical total volume of groundwater at the start of recession

was calculated. This total volume has been interpolated from the recession straight lines and

their corresponding α values (figs. 32, 33 and tabs. 4 ,5), which are linked to single unique

discharge regimes and volumes.

Hydrographs of both of the investigated springs show two iterative linked recession straight

lines along their run with the respective inclination values α1 and α2. Pleier Spring also

features a third recession value, α3 (see also fig.34 and fig.35). By applying the equations

mentioned in chapter 2.4.3, it is possible to calculate not only the theoretical total volume, but

also the single volumes for each discharge micro regime linked to an α value.

At Roach Spring, the event water volume V1 of 138,03 million litres (fig.37 tab.6) runs off at

the beginning of the recession, followed by the base flow volume V2 with 812,16 million litres

(fig.37, tab.6). A total volume V0 of 950,19 million litres (tab.6) can theoretically be

discharged from the beginning of the recession to the end of the hydrograph, under the

assumption that α values remain constant.

The values to calculate these volumes have been selected from the period of 11.03.2009 to

29.03.2009 (see tab.5). At this part of the hydrograph of Roach Spring both α1 and α2 can

be identified clearly and the end of the recession is clearly marked by a rising limb.

(tab.6): initial discharge rates Q01 and Q02 and the corresponding volumes of water V1 and V2

(fig.37) of Roach Spring, V0 is the total initial volume of water at the beginning of discharge

Q01 (l/s) 317,4 V1 (l) 138,03 * 10^6

Q02 (l/s) 188 V2 (l) 812,16 * 10^6

V0 (l) 950,19 * 10^6

55

t2time after recession started

t1

100

1000

200

300

400

500600700800900

disc

harg

e(l/

s)lo

g10

α1α2

V2

V1

Q01

Q02

(fig.37): recession straight lines of Roach Spring from (fig.33), with the two micro regimes of discharge

and corresponding volumes V1 and V2 (tab.6), Q01 marks start of recession, t1 and t2 correspond to

∆t (tab.5)

Pleier Spring shows one relatively fast draining discharge volume V1 (fig.38, tab.7) with

21,72 million litres, and the intermediate V2 (fig.38, tab.7) featuring a volume of 44,64 million

litres which can flow out. The base flow is V3 (fig.38, tab.7) with 302,4 million litres, the total

available volume V0 (tab.7) is 368,7 million litres.

The values to calculate these volumes have been selected from the period of 07.04.2009 to

03.09.2009 (see tab.4). At this part of the hydrograph of Pleier Spring α1, α2 and α3 appear

consecutively. Between the final discharge of α2 straight line and initial discharge α3, a

disturbance is visible on the hydrograph (fig.32), to perform a consistent calculation, the

recession straight lines in fig. have been composed by parallel adjustment of α3 line.

(tab.7): initial discharge rates Q01,Q02 and Q03 and the corresponding volumes of water V1,V2 and

V3 (fig.38) of Pleier Spring, V0 is the total initial volume of water at the beginning of discharge

Q01 20,62 V1 (l) 21,72 * 10^6 Q02 17,1 V2 (l) 44,64 * 10^6 Q03 14 V3 (l) 302,4 * 10^6 V0 (l) 368,7 * 10^6

56

time after recession started

10

20

30

disc

harg

eQ

(l/s

)lo

g10

α1

α2α3

V3

V2

V1

0

Q01

Q02

Q03

t1 t2 t3

(fig.38): recession straight lines of Pleier Spring from (fig.32), with the two micro regimes of discharge

and corresponding volumes V1, V2 and V3 (tab.7), Q01 marks start of recession, t1, t2 and t3

correspond to ∆t (tab.4)

It is observable, that Roach spring has the much bigger resources for the discharge of water

in both event influenced and base flow volumes. Both springs discharge the biggest volumes

from their base flow volumes V2 (Roach) and V3 (Pleier). The base flow of Roach Spring is

about two times bigger than the base flow of Pleier, the total theoretical discharge V0 at

Roach is three times higher. The relation of base flow to event water volumes is at Roach

Spring roughly 6:1, at Pleier Spring this relation is 4,5:1, if V1 and V2 are considered as

event water.

57

4.2.5 Aquiclude of western Turiawald

The height difference between the verified position of the aquiclude trace on the southern

escarpment, and springs or wetlands (except Roach Spring) on the western slope is in

average approximately 140 meters. This indicates an average dip angle to the northwest for

the aquiclude of about 4,5 degrees below the mass movement and western Turiawald.

Considering this information together with mapping results (outcrops of fine clastics and coal,

tappings of springs, wetlands, see fig.30) and known positions of coal and fine clastics on the

north western slope, the position of the aquiclude bed can be located in the area between the

contour lines of 630 and 660 meters above sea level, illustrated by the hypothetical trace of

the aquiclude (fig.36). This assumption can be made for the northern part of the western

slope.

Due to the lack of outcrops of fine clastics and coal or signs of water on the surface of the

southern area of the western slope, the run of the aquiclude in this area was interpolated by

overlapping its dip angle with the topography. Therefore the supposed run of the aquiclude is

similar to the verified trace on southern slope of Turiawald, but moved about 30 meters

downwards, and can be located around a level of approximately 645 meters of altitude as

shown in (fig.36).

(fig.36): run of the hypothetic aquiclude on the western slope of Turiawald

58

5. Discussion and interpretation

5.1 Structural geology and morphology

5.1.1 Turiawald Plateau

The altitude of the plateau is descending from the south east to the north west (fig.25). The

formations of crystalline rocks, i.e. marbles and diaphtorites in the south and south east of

Turiawald (fig.8), are known to be in contact with the Sattnitz Conglomerate. Thrust planes

and slickensides of St. Ruperti outcrop do have an average dip direction to the north west

(fig.17).

Since the north western part of Turiawalds conglomerates is underlain by fine grained clastic

formations and the south eastern part by subjacent crystalline rocks (fig.8), it can be

assumed, that the plateau bears on the uplifted competent crystalline rocks in the southeast,

while moving downwards on the incompetent layers of fine clastics in the northwest. The fine

grained clastic formations are squeezed out in western direction by the pressure of the

overlying conglomerates. The resulting mass deficit of the subjacent clastics caused the

brittle conglomerate layer to bow and finally break.

This occurs mainly along preexisting discontinuities, as shown by the correlation of strike

directions of joints, sinkholes and lineaments of Turiawald with striking of joint sets of the

basement rocks and regional lineaments (fig.21 and fig.24).

In addition the mass movement also creeps down western slope, therefore it is assumed that

below the western part of Turiawald friction between the moving fine clastics and the

constraining conglomerate induces horizontal normal tensile stress upon the brittle top layer,

this leads to the formation of joints and fractures with both orthogonal and perpendicular

directions to the border of the conglomerate layer (fig.25 and fig.26).

At the south eastern part of the plateau, a NW/SE striking single joint opening is located

which shows an aperture of one meter and a length of approximately 40 meters. Along the

lengthening of this crack also several sinkholes can be found aligned in a row, following the

strike of the joint. This indicates a tectonic origin of the sinkholes, while no signs could be

found to verify the assumption, that these sinkholes are formed by karst formation, as

explained by other authors.

The large numbers of sinkholes, depressions and joint openings appearing on the Turiawald

plateau, also in a respective distance from the escarpments, and the general undulous

59

morphology of the plateau indicate a progressive, backwards directed advance of the slope

tectonics, which causes the platform to break up. This occurs not only in the border areas of

the plateau and its centre, but also towards the most elevated south eastern area (fig.25).

The presence of water at the contact area between conglomerate and basement rocks is

assumed, due to the little hydraulic permeability of the basal fine clastic formations and

crystalline rocks. This may reduce friction and contribute to movement of conglomerate

blocks above the less permeable layers, resulting in an increase of joint and fissure

openings.

5.1.2 Mass Movement of western slope

During Wuerm Glacial Period, Turiawald plateau was covered by several hundreds of meters

of ice from the Drau Glacier, which was flowing from west to east (Fellner 1993). The ice also

supported the western flank of the plateau. When the glacier retreated, the counter bearing

of the ice was removed and the over steepened western flanks of Turiawald started to move.

Blocks are separated from the in situ conglomerate of the plateau by joint planes which were

preexisting or caused by breakup of the conglomerate layer. Conglomerate blocks and slabs

that are fully separated from the platform by joint planes, and do have at least one vertical

joint plane which daylights to the west, are suspected to move downhill.

The type of mass movement in this area can be classified as complex mass movement (after

Hutchinson 1988), for the following reasons:

At least three different types of slope failure at the rock faces of Turiawald could be identified

(fig.19d and fig.29):

- rock toppling failure, which is especially predominant in the northern area of western

slope

- rock slumping failure, which is occurring only in a few cases

- translational movement of blocks, also only observed in little numbers

Blocks and big mass movement bodies situated at a minimum distance of 500 m of the rock

faces also show these types of movement.

60

Because of the fact, that these different mechanisms of movement appear altogether, it is

assumed, that no single sliding plane is present within the mass movement body which

consists of conglomerate blocks and debris as well as fine clastic rocks. There are also no

incidents of recent rapid movement known at western slope itself, but several indicators for

slow movement have been observed:

-Undulatory topography

-bow shaped growth of trees

-roof fall incidents affecting the coal mine “Augstistollen”

-tilted cairns

-convex slope form

Considering these aspects, the mass movement can also be described as creep (after

GLAWE & MOSER, 1989 and Hutchinson, 1988).

At the foot of western rock faces at two location blocky debris from past time rock falls can be

found. It is assumed that this debris broke off during the initial stage of a slab or block being

removed from the in situ rock mass, representing its crown or upper part.

Since fine clastics formations and coal beds found inside the mass movement do have the

same structural orientation as their respective linked block, it is stated that these formations

are brought up to daylight by the rotation of the blocks.

Since there are no fine clastics or coal occurrences at the surface of the southern part of the

western slope, it may be stated that in this area the rotational movement of blocks is less

intense as in the north, which is also indicated by the structural data (fig.29).

61

5.2 Hydrogeology

5.2.1 Analysis and interpretation of hydrograph and parameter graphs

Roach shows features of a karst spring, including a low quotient of discharge NQ/HQ of 0,05

and strongly varying minimum NQ and maximum HQ discharge, as well as relatively high α

values of an order bigger than 10-² for both base flow and event water (tab.8 and tab.9).

Since no clear signs of karstification were found on Turiawald and its foreland, it is assumed

that these characteristics are caused by open, well connected joints and fissures on the

plateau and voids provided by the mass movement body.

Hydraulic reaction due to precipitation events appears within one day or less and the transit

time of water moving through the aquifer conduits is approximately four days, shown by

electric conductivity decreases during increase of discharge.

(tab.8): MQ, NQ, HQ and discharge quotient NQ/HQ of Pleier and Roach springs from 2008 to 2009,

calculated from day mean values.

june08-july09

june08-july09

Pleier Roach

NQ (l/s) 6,9 21,33

HQ (l/s) 21,37 403,32

MQ (l/s) 12,48 103,61

NQ/HQ (l/s) 0,32 0,05

(tab.9): average discharge coefficients of the springs Pleier and Roach

Pleier α [1/d] Roach α [1/d] α1 0,0125 α1 0,0795

α2 0,004 α2 0,0275

α3 0,0035

Pleier spring has a quotient of discharge of 0,32 and does not show strong variations in

minimum and maximum discharge, what is characteristic for a more retentive storage milieu

(tab.8). Pleier Spring only has one single value, α1, which shows an order of 10-2 and

represents a relatively fast flow out. The coefficients α2 and α3, which drain the bigger

volumes, indicate by their magnitude of 10-3 (tab.9) discharge from aquifers of smaller voids

like narrow joints and aquifer matrix.

Hydraulic reaction to precipitation can take place within one to three days, the transit time

indicated by a decrease of electric conductivity is only fifteen hours.

62

Roach Spring often shows for a short period an increase of electric conductivity at the

beginning of a rising limb on the hydrograph (fig.35). It is assumed that a part of the water

remains in a storage regime where it interacts strongly with the carbonate conglomerate and

CO2, because of that it becomes relatively higher mineralized there. Such a regime could be

provided by the mass movement body and the big surface of the conglomerate debris. This

mass movement water is then flushed out first by an increasing hydraulic gradient.

The electric conductivity graph of Pleier Spring shows almost only a decrease due to

changes of discharge (fig.34). Therefore it is assumed, that infiltrating water moves into an

aquifer where due to a smaller surface of the aquifer rock or the absence of CO2 no such

reactions take place and the spring is very little influenced by a debris body.

There is an inconsistence between discharge coefficients, discharge quotients and the time

lags of water transit and hydraulic reaction.

The α values and NQ/HQ quotient of Roach Spring show characteristics of a fast draining

spring, and also only short time passes between precipitation and hydraulic reaction, but the

transit time of the water through the aquifer conduits is several days.

The fast hydraulic reaction and the high maximum discharge can be explained by rapid

infiltration of precipitation water into the mass movement body, illustrated by α1 which is

linked to the theoretical discharge volume V1 and resembles 14% of total discharge from

Roach.

Water flowing from the plateau to Roach Spring has to pass through the mass movement

first, where fresh water mixes with older and higher mineralized water. It is assumed that this

process takes several days, and that water outflow from the plateau is buffered by the mass

movement body, what is indicated by the smaller coefficient α2. This assumption can explain

the time lag between maximum discharge increase and electric conductivity decrease.

Pleier Spring is mainly characterized by α2 and α3 values of similar magnitude indicating

slower discharge, but also α1 with a magnitude typical for fast discharge. The latter indicates

fast transport of water through large voids like joint openings, what is indicated by the

presence of lineaments on the northern plateau. V1 is the linked theoretical discharge

volume of α1 and represents 5% of total discharge of Pleier.

The discharge coefficient α1 is also held responsible for the fast dilution causing the

decrease of electric conductivity, while α3 illustrates slow discharge from narrow joints or a

matrix aquifer. Coefficient α2 is assumed to be a intermediate value between α1 and α3.

Although Roach Spring has a recharge area of 3,9 km² which is only 65% of the total

hydrogeologic catchment area of Turiawald (6.1 km²), it discharges with 106,3 (l/s) 82% of

63

the total average annual discharge (116,1 l/s, = sum of MQ values of Roach and Pleier

Springs, plus anticipated 10 (l/s) from Hojoutz water gallery) measured in 2008/2009. Pleier

Spring has a recharge area of 0,8 km² which represents 13% of the total catchment area, the

annual average discharge of 12.5 (l/s) represents 11% of the total discharge of Turiawald.

The relatively high discharge of Roach Spring compared to its recharge area can be

explained by the inclination of the aquiclude, which is gently dipping from south east to north

west, thus the groundwater flows generally in this direction.

5.2.2 Aquiclude morphology

At the northern western slope, the basal clastics of Penken Formation are moving downhill

attached to their respective blocks. Thus, they are affected by rotation of blocks, which

makes the fine clastics layer which acts as aquiclude discontinuous and diffuse in this area.

An uneven profile of the aquiclude containing both morphologic heights and depressions has

to be assumed, outcrops of fine grained clastics may be the height points of such a structure.

Because of this, the position of the aquiclude cannot be determined more exactly due to the

information available and has to be considered variable (fig.36).

There have no occurrences of fine clastics, coal or wetlands been found at the surface of the

southern part of the western slope. As explained before, translational movement of blocks in

this area is predominant which is also indicated by structural data (fig.29). This type of

downward movement of blocks also displaces the underlying fine clastics, but they do not

daylight, what indicates that the basal neogene clastics layer is continuous in this area.

Because of the fact that the thrust planes of the marbles of St.Ruperti are dipping to the

northwest (fig.17), it may be assumed, that the whole south eastern part of Turiawald, is

underlain by crystalline rocks, which was also assumed by preliminary studies (Poltnig et al.

2007, Griem et a. 1992, fig.7 and fig.8). It is suggested, that these crystalline rocks also act

as aquiclude bed in this area.

Crystalline and fine grained clastic parts of the aquiclude seem to dip towards north west.

Into this direction runs the water from the western part of the catchment area, which is

illustrated by the fact that all springs featuring high discharge rates are on the northern and

western flanks of the plateau. The NE/SW striking, valley shaped lineament in which Roach

spring is situated (fig.36) can probably act as draining element and direct the groundwater

westward from the mass movement area to the deepest point of the slope where Roach

spring is located. The presence of several coal mines in this area should also be taken in

consideration, since they can act as drainage channels.

64

6. Conclusion

6.1. Failure mechanism and kinematics

The conglomerate platform Turiawald is broken up and showing a down stepping

morphology from the south east to the north west (fig.37). The southerly subjacent crystalline

basement provides uplift to the most south eastern conglomerate slab bearing on it, while the

rest of the platform moves downhill in north western direction. The thrust planes of the

crystalline basement dipping to the north west are assumed to form a gliding plane for the

hanging conglomerates in the south east, while below the north western parts of Turiawald

incompetent fine clastic rocks enable gliding of the hangingwall.

The expansive downward movement of conglomerate slabs and blocks results in an

undulous morphology of the plateau, which consist of depressions and elevations. These

appear to be similar to horst and graben structures.

The break up of the plateau is also illustrated by its lineaments, joints and sinkholes. These

have main strike directions correlating to the strike of joints sets of basement rocks and

regional lineaments. The latter are linked as Riedel shear planes to the Periadriatic Line.

Thus it is assumed, that the joint sets and lineaments of Turiawald are mostly formed along

preexisting discontinuities.

The most sinkholes, joint openings and joint sets can be found in the west of Turiawald

Plateau and at the foot of its western rock faces, often featuring orientations of strike

directions parallel and perpendicular to the escarpments.

At the western flank of Turiawald plateau, the incompetent footwall of fine clastics of Penken

Formation evades the pressure from the overlying Sattnitz Conglomerate and are squeezed

out into the western foreland. As a consequence of this movement, and the resulting mass

deficit, the competent hangingwall conglomerate starts to sink down and breaks up into

distinct blocks. These continue to move further downhill and break up due to the movement.

Together with conglomerate debris and fine clastic material these blocks form the mass

movement body of western slope.

The blocks of western slope show the following movement types:

- rock toppling failure

- rock slumping failure

- translational movement of blocks

65

As a résumé the whole mechanism of deformation of western Turiawald Plateau and the

consequent mass movement of its western foreland can be described as a system “hard on

soft” (after Poisel and Eppensteiner 1989).

Because of the simultaneous appearance of block failure modes, it is assumed, that no

single failure plane is present and no fast displacement takes place. This suggests creep as

the type of movement of the mass movement body below the western rock faces (after

Glawe, Moser, 1989). The type of mass movement is due to the fact that several modes of

failure appear together classified as complex mass movement (after Hutchinson 1988).

An imminent danger of being affected by the mass movement of Turiawald or a consequent

effect like rock fall can be excluded for the villages Roach and Penken. The minimum

distance between the rock faces and buildings is roughly 2 kilometres but rock fall debris was

only found directly at the toe of the faces of the western escarpment. Dense woods and soft

underground would provide proper damping space for such an incident. There have no signs

been found for significant recent rapid failure or movement of blocks at the faces, no signs of

fast movement were observed at the mass movement body.

Sattnitz Conglomerate

Penken Formation

debris

crystalline basement

aquiclude

SE

NW

Roach Spring

(fig.37) sketch map of Turiawald, moving downwards to NW, thickness of crystalline basement is

unknown

66

6.2 Hydrogeology

Both investigated springs are bound to the lithologic contact of permeable Sattnitz

Conglomerate impermeable and neogene fine clastic rocks of Penken Formation.

The two springs show distinct features in their discharge behaviour, which are bound to

geologic and morphologic features of their respective recharge areas. Joint openings and

sinkholes at the surface of the plateau are assumed to enforce infiltration of precipitation and

therefore prohibit surface runoff.

While Pleier Spring is situated close to the northern escarpments at 650m altitude, Roach is

located at the base of the mass movement area at 550 meters (fig.37), ca. one kilometre off

the plateau margins.

Considering discharge quotient and coefficients, Pleier is draining an aquifer situated within

the plateau, which mainly consists of narrow joints or aquifer matrix, only a small part of the

discharge is related to fast infiltration of precipitation due to joint openings.

Roach shows clear characteristics of a karst spring, although these are also related to the

joint openings of the broken platform of Turiawald as well as the resulting mass movement.

In opposite to Pleier Spring, Roach is strongly influenced by the mass movement. On the one

hand it allows rapid infiltration of precipitation due to the large voids of the conglomerate

debris, on the other hand it buffers water flowing out of the plateau.

The mass movement also influences the position and morphology of the aquiclude on

western slope. The aquiclude consists of crystalline rocks of the prepermian basement rocks

in the south eastern part of Turiawald, and neogene fine clastics in the west and norh west. It

is gently dipping towards the north west, where also the strongest discharging spring, Roach

spring is located (fig.37).

Within the mass movement area, the fine clastic layer has been displaced and discontinued

by the downward creep of the slope, and rotational movements of conglomerate blocks

formed a molded surface of the aquiclude in the north of western slope (fig.37). In the south,

the aquiclude has been moved downwards but seems to be still continuous.

The annual average discharge of for the year 2008/2009 Roach is 103,61 (l/s), Pleier

discharges 12,48 (l/s). A theoretical total discharge of 950,2 million litres can be flow out from

Roach, and 368,7 million litres from Pleier until the storage is empty.

67

7.Literature Bauer, F. K., Cerny, 1., Exner, C., Holzer, H.-L., v. Husen, D., Loeschkc, J., Suette, G. &

Tessensohn, F. 1983. Erläuterungen zur geologischen Karte der Karawanken 1:25,000,

Ostteil. Geol. Bundesanstalt, Wien.

Bögel, H. 1975. Zur Literatur über die "Periadriatische Naht“. Verh. geol. Bundesanstalt

1975, 163-199.

Boyer, S.E., Elliott, D., 1982. Thrust systems. American Association of

Petroleum Geologists Bulletin 66, 1196–1230

Brosch, F.J. & Kurz, W.: Fault damage zones dominated by high-angle fractures within layer-

parallel brittle shear zones: examples from the Eastern Alps.- Geol. Soc. Spec. Publ., 299,

75-95, 2008.

Bundesamt für Eich– und Vermessungswesen 2005 Österreichische Karte 1:50.000 (ÖK 50)

Claasen et al., Die Permotrias und ihr Grundgebirge zwischen Faaker See und Turiawald

südöstlich von Villach (Kärnten/Österreich), Jb.Geol. B.A., S 391-413

Eisbacher G. H., (1996): Einführung in die Tektonik. 374 S., Ferdinand Enke Verlag, Stuttgart, 1996.

Fellner, D., 1993 , Die Massenbewegungen der Sattnitz (Kärnten, Österreich), Jb.Geol. B.A.,

S 315-325

Glawe U. & Moser M., (1993): Meßtechnische und theoretische Bearbeitung von

Bergzerreißungen und Blockbewegungen. Felsbau 11 (1993) Nr. 5, pp.235-250.

Gosen, W., von 1989. Fabric development and the evolution of the Periadriatic Lineament in

southeast Austria. Geol. Mag. 126, 55-71.

Griem et al., 1992, Sedimentologie und Sedimentpetrographie des tertiären

Sattnitzkonglomerats zwischen Villach und Klagenfurt (Kärnten, Österreich), Jb.Geol. B.A., S

27-36

68

Hancock, P. L., 1985, Brittle microtectonics: principles and practice, Journal of Strucural

Geology, Vol.7, pp. 437 to 457

Hölting B., & Coldewey W. G., (2005): Hydrogeologie, 6. edition (2005), Ferdinand Enke

Verlag, Stuttgart, 348 S.

Hutchinson, J.N. (1988): General report: Morphological and geotechnical parameters of

landslides in relation to geology and hydrogeology. – In: BONNARD, C. (Ed.): Proc., Fifth

International Symposium on Landslides, A.A. Balkema, Rotterdam, Vol.1, 3-35.

KaGis Kaernten, Amt der Kärntner Landesregierung Abt.20 / Landesplanung, DHM 10m der

triangulierungs Blattschnitte

Kahler, E, 1953. Der Bau der Karawanken und des Klagenfurter Beckens. Carinthia II, pp. 5-

78.

Klaus, W., 1956. Mikrosporenhorizonte in Stid- und Ostkarnten. Verhandlungen der

Geologische Bundesanstalt, Wien, pp. 250-255.

Kresic N., (2007): Aquifers and Aquitards, S.224-245, Hydrogeology and Groundwater

Modelling,

807 S.; Boca, Raton, Florida, 2007

Langguth H.R., Voigt R., 2004, Hydrogeologische Methoden, Springer, Berlin, pp. 203

Laubscher, H. P. 1970. Das Alpen-Dinaridenproblcm und die Palinspastik der südlichen

Tethys. Geol. Rdsch. 60, 813-833.

Laubscher H. P. 1983. The late Alpine (Periadriatic) intrusions and the lnsubric Linc. Mere.

Soc. geol. Italia 26, 21-311.

Laubscher, H. P. 1988. Material balance in Alpinc Orogeny. Bull. geol. Soc. Am. 100, 1313-

1328.

Madritsch H & Millen B. M. J., (2007): Hydrogeologic evidence for a continuous basal shear

zone within a deep-seated gravitational slope deformation (Eastern Alps, Tyrol, Austria).

Landslides 4 (2007), 149-162.

69

Maillet E., (1905): Essais d´hydraulique souterraine et fluviale, 218 S.; Paris, 1905.

Meschede M. 1994, Methoden der Strukturgeologie, Enke, Stuttgart, 112 pp.

Nemes et al., 1997, The Klagenfurt Basin in the Eastern Alps: an intra-orogenic decoupled

flexural basin, Tectonophysics, P 189-203

Nemcok, A, (1977): Geological/Tectonical Structures – an essential condition for Genesis

and Evolution of Slope Movements. Bull. Int. Assoc. of Engineering Geology, Vol.16, 127-

130, Krefeld

Papp, A., 1951. Ober die Altersstellung der Terti/irschichten von Liescha bei Priivali und

Lobnig. Carinthia II 141, 62-64.

Passchier, C.W. & Trouw, R.A.J. (2005): Microtectonics 2nd edition. Springer, Berlin

Heidelberg.

Poisel et al., 1988, Gang und Gehwerk einer Massenbewegung Teil1, Geomechanik des

Systems „Hart auf Weich“, Felsbau 6, S189-194

Poisel et al., 1989, Gang und Gehwerk einer Massenbewegung Teil2, Massenbewegungen

am Rand des Systems „Hart auf Weich“, Felsbau 7, S 16-20

Polinksi, R.K., Eisbacher G.H., 1992, Deformation during polyphase oblique convergence in

the Karawanken Mountains, southeastern Alps, Journal of structural geology, Vol. 14,

pp1203 to 1213

Poltnig et al., 2007, Hydrogeologie Sattnitzberge-Sattnitzplateau-West KA42/04, unveröff.

Ber., Inst. f. Wasser Ressourcen Management, S 110

Sauter, M., 1992, Quantification and Forecasting of Regional Groundwater Flow and

Transport in a Karst Aquifer, (Gallusquelle, Malm, SW. Germany), TGA, C13, 150 pp.

Schmid, S. M., Aebli, H. R., Heller, F. & Zingg, A. 1989, The role of the Periadriatic Line in

the tectonic evolution of the Alps. In: Alpine Tectonics (edited by Coward, M. P., Dietrich, D.

& Park, R. G.). Spec. Pap. geol. Soc. Am. 45, 153-171.

70

Schönlaub, H. P. 1979. Das Paläiozoikum in Osterreich. Abh. geol. Bundesanstalt 33, 124S.

Tollmann, A., 1985. Geologie von Osterreich (Zentralalpiner Teil), 2. Deuticke, Wien, 680 pp.

Winkler, G., Poltnig, W. & J. Schlamberger (2008): Hangtektonische und tektonische

Beeinflussung des Grundwassersystems Sattnitz,.- Computeranwendungen in Hydrologie,

Hydrogeologie und Geologie, Beiträge zur COG-Tagung Salzburg 2007, Wichmann,

Heidelberg: 38-46

Wyllie, D.C. & Mah, C.W. (2004): Rock Slope Engineering: Civil and Mining. 4th ed,

SponPress, London.